1. Technical Field
The present invention relates to cell module structures equipped in electric cars, hybrid electric cars, and the like, as a driving power supply. The cell modules in the invention include any type of charging element device, including cells such as nickel hydrogen batteries and lithium batteries; and energy storage devices such as double layered capacitors (ultra-capacitors).
2. Background Art
As a cell module in which plural cells are serially connected to each other, a conventional one is exemplified in which plural cylindrical or rectangular cells having a positive terminal and a negative terminal arranged at an end thereof are arranged in parallel, and the positive terminal and the negative terminal in adjoining cells are connected to each other via a bus bar so that the cells are connected to each other. The bus bar is generally mounted to the terminals by bolts or nuts in the assembly of the cell module.
FIG. 18 shows an example of a cell 100 and a bus bar 110 for a conventional cell module. In the example, a positive terminal 101 and a negative terminal 102 are arranged and project at an end of a cylindrical cell 100. The bus bar 110 consists of a positive bus bar 111 and a negative bus bar 112, which are insulated from each other and are penetrated by bolts 120 and 120, which are screwed to the positive terminal 101 and the negative terminal 102 so as to secure and serially connect them to each other.
In the conventional cell module structures in which plural cells are connected to each other according to the connecting feature in FIG. 18, the labor for connecting the terminals by a bus bar is substantial since the task in which the bus bar is positioned with respect to the terminal and then the bolt is secured thereto must be repeated. Furthermore, a large space for operating a securing tool is required for securing the bolts, and care to avoid short circuiting by the tool is necessary, and the connecting working is therefore further complicated.
In order to reduce the contact resistance in the connecting portion, the terminal and the bus bar must be rigidly secured. However, the load exerted on the connecting portion increases due to deformation thereof due to vibration and temperature changes, and the condition of the connection may therefore be deteriorated. In order to reduce the load exerted on the connecting portion, it has been proposed that the cells be supported by holding members. However, this proposal results in increase in the number of parts and complication of the structure.
In general, the area occupied by overall the cell and the cell module is readily large in the cell in which a positive terminal and a negative terminal are arranged at an end thereof, and this feature is disadvantageous for vehicles which are required to effectively utilize limited space.
It has been proposed to change the shapes of the positive terminal and the negative terminal to avoid misassembly in which the positive terminals are connected or negative terminals are connected. However, since the terminals are usually formed as protrusions, misassembly can not be completely avoided. In addition, since the terminals are formed as protrusions, the terminals are often damaged by mishandling thereof. As a result, sufficient electrical contact cannot be obtained, or the terminals may short circuiting in some cases.
Therefore, an object of the present invention is to provide cell module structures which can satisfy the following requirements.
(1) Cells can be easily connected and electrical resistance can be reduced.
(2) Fine layout of cells can be performed and space is used effectively.
(3) Misassembly, damage and short circuiting of cells can be avoided.
The present invention provides a cell module structure in which cylindrical cells are connected to each other via a terminal connecting portion of a bus bar plate, wherein an inner cell terminal and an outer cell terminal having different polarities are coaxially aligned at an end of the cell; an inner connecting terminal and an outer connecting terminal corresponding to the inner cell terminal and the outer cell terminal of the cell are coaxially aligned in the terminal connecting portion of the bus bar plate; the inner cell terminal and the outer cell terminal of the cell are connected to the terminal connecting portion of the bus bar plate in a connected condition in which the outer cell terminal of the cell contacts the outer connecting terminal of the terminal connecting portion, and the inner cell terminal contacts the inner connecting terminal. The invention includes a feature in which the terminal connecting portion of the bus bar plate has a contacting portion with each cell terminal of the cell, the each cell terminal is welded or adhered to the contacting portion. The terminals (positive and negative terminals) according to the invention are coaxially aligned as the inner cell terminal and the outer cell terminal at an end of the cell. The inner connecting terminal and the outer connecting terminal corresponding to the terminals of the cell are arranged in the terminal connecting portion of the bus bar plate. Each terminal of the cell is brought into contact with a terminal of the terminal connecting portion, and thus a module is formed. In the invention, since the positive and negative terminals are coaxially aligned, the cell is easily connected to the terminal connecting portion, and the distance for electrical transmission can be extremely short, thereby reducing the electrical resistance. In addition, the space occupied by overall the cell and the cell module can be reduced, so that limited space can be effectively utilized, and fine layout can be achieved when the plural cells are arranged. The connecting operation can be more easily performed since the operator need not confirm the polarity of the terminal of the cell in connecting the cell to the terminal connecting portion, and misassembly of the same polarity and short circuiting due to this can be avoided.
The present invention further provides a more specific cell module structure, wherein: an inner cell terminal and an outer cell terminal having different polarities are coaxially aligned at an end of the cell, at least the outer cell terminal is formed into a cylinder and has a screw portion on an inner surface or an outer surface thereof; an inner connecting terminal and an outer connecting terminal corresponding to the inner cell terminal and the outer cell terminals of the cell are coaxially aligned at the terminal connecting portion of the bus bar plate, and a screw portion screwed into the screw portion of the outer cell terminal is formed at the outer connecting terminal; the inner cell terminal and the outer cell terminal of the cell are connected to the terminal connecting portion of the bus bar plate in a connected condition in which the screw portion of the outer cell terminal in the cell is screwed to the screw portion of the outer connecting terminal in the terminal connecting portion, so that the inner cell terminal is brought into contact with the inner connecting terminal.
According to the invention, the cell is rotated around the axis thereof, the screw portion provided in the outer cell terminal of the cell is screwed and secured to the screw portion provided in the outer connecting terminal in the terminal connecting portion. In this construction, the outer cell terminal of the cell contacts the outer connecting terminal of the terminal connecting portion by screwing. The inner cell terminal of the cell is brought onto contact with the inner connecting terminal of the terminal connecting portion by the action of the screw. For this connected condition, the inner cell terminal and the outer cell terminal are connected to the terminal connecting portion of the bus bar plate.
The present invention further provides another specific cell module structure, wherein: an inner cell terminal and an outer cell terminal having different polarities are coaxially aligned at an end of the cell, the inner cell terminal is formed into a column and has a screw portion on an outer surface thereof; an inner connecting terminal and an outer connecting terminal corresponding to the inner cell terminal and the outer cell terminals of the cell are coaxially aligned at the terminal connecting portion of the bus bar plate, and a screw portion screwed into the screw portion of the inner cell terminal is formed at the inner connecting terminal; the inner cell terminal and the outer cell terminal of the cell are connected to the terminal connecting portion of the bus bar plate in a condition in which the screw portion of the inner cell terminal in the cell is screwed to the screw portion of the inner connecting terminal in the terminal connecting portion, so that the outer cell terminal is brought into contact with the outer connecting terminal.
In the invention, the screw is formed in the inner cell terminal, and the cell is rotated around the axis thereof, so that the screw portion of the inner cell terminal of the cell is screwed and secured to the screw portion of the inner connecting terminal of the terminal connecting portion. For this operation, the inner cell terminal of the cell contacts the inner connecting terminal of the terminal connecting portion by the screw securing. The outer cell terminal of the cell is brought into contact with the outer connecting terminal of the bus bar plate by the screw action of the cell. In this connected condition, the inner cell terminal and the outer cell terminal of the cell are connected to the terminal connecting portion of the bus bar plate.
According to the connected condition of the terminals by the screw securing, sufficient contact area between the terminals can be obtained and the distance for electrical transmission can be extremely short, so that the electrical resistance can be greatly reduced. Furthermore, since the rigidity of the connected condition between the terminal of the cell and the terminal of the terminal connecting portion can be improved, the connected condition of the terminals can be rigidly maintained, and the electrical resistance can be reduced. In particular, in the case in which the screwing portion of the cell is provided to the outer cell terminal, the rigidity in the connected condition is improved more than in the case in which the screwing portion is provided at the inner cell terminal, so that the above function can be more adequately obtained.
In addition, the cell can be connected to the terminal connecting portion merely by screwing the cell to the terminal connecting portion of the bus bar plate, so that securing members such as bolts and nuts, and securing tools, are not needed. Therefore, the connecting operation can be performed with great ease, and the space necessary for the operation can be reduced. In addition, the space occupied by overall the cell and the cell module can be reduced, so that limited space can be effectively utilized. The connecting operation can be further facilitated since the operator need not confirm the polarity of the terminal of the cell in connecting the cell to the bus bar plate, and misassembly of the same polarity and short circuiting due to this can be avoided.
The essential feature of the invention is the connecting structure for the cell to the terminal connecting portion of the bus bar plate, and this feature is greatly preferable for constructing a cell module connecting plural cells. According to the preferable feature of the invention, the plural terminal connecting portions are straightly aligned on a surface of the bus bar plate, and the plural cells are connected to the terminal connecting portions in the connected condition. According to another preferable feature of the invention, and the plural terminal connecting portions are straightly aligned on both surfaces of the bus bar plate, and the plural cells are connected to the terminal connecting portions in the connected condition.
The distance between the adjoining cells can be shortened by serially connecting the plural cells as in the above, fine layout of the cells can be obtained, and whole of the cell module can be compact and the space can be effectively utilized.
The invention provides the following features.
(1) The outer cell terminal of the cell may be cylindrical, and the inner cell terminal may be disposed thereinto. The height of the outer cell terminal may be higher than that of the inner cell terminal. For this feature, the inner cell terminal is protected by the outer cell terminal. When this feature is applied to the invention in which the screw portion is formed in the inner surface of the outer cell terminal, the end surface of the inner cell terminal and screw portion of the outer cell terminal, which are essentially electric transmittal portions, will not be damaged. Alternatively, when the feature is applied to the invention in which the screw portion is formed on the outer surface of the inner cell terminal, the end surface of the outer cell terminal and screw portion of the inner cell terminal, which are essentially electric transmittal portions, will not be damaged. In both cases, problems, in which sufficient electric contact is not obtained, will be solved, and short circuiting of both terminals will be prevented.
(2) In contrast to the feature in (1), the inner cell terminal may be higher than the outer cell terminal so as to project therefrom.
(3) An insulating member may be held between the outer cell terminal and the inner cell terminal of the cell, thereby reliably preventing short circuiting. The insulating member may be higher than the outer cell terminal and the inner cell terminal so as to project therefrom. In this case, the insulating member may protect the outer cell terminal and the inner cell terminal.
(4) A conductive elastic member may be held between connecting portions of the terminals, which are brought into contact to each other rather than the contact by screws. The terminals are electrically contacted to each other via the elastic member. Herisert may be preferably used for the elastic member.
(5) A tool engaging portion for rotating the cell by a tool around the axis thereof may be provided at an end of the cell, which end is opposite to the end in which the outer cell terminal and the inner cell terminals are provided. Holes or protrusions having polygonal or star-shaped cross section may be employed for the tool engaging portion. According to this feature, when the cell is screwed and secured to the terminal connecting portion of the bus bar plate, strong securing torque can be applied to the cell by a tool such as a wrench fitted to the tool engaging portion, and the connecting strength can be improved.
(6) As an arrangement of the tool engaging portion in (5), a portion of the cell may be a polygon. Rectangular or hexagonal cross section may be applied for rotating the cell by a tool such as a cylindrical wrench. The polygonal cross section may extend over the entire length of the cell. This feature also can yield the advantages in (5).